pngbai.sh

#!/bin/sh

## Packages:
# brew install pngcrush
# brew install optipng
# brew install advancemame
# brew install https://raw.github.com/adamv/homebrew-alt/23f9084410476da1fcaf946f24f4dde47fe888ea/non-free/pngout.rb

function usage {
  echo "Usage: $0 infile outfile"
  exit 1
}

if [ ! $# -eq 2 ]; then
  usage
elif [ ! -f $1 ]; then
  usage
fi

infile=$1
outfile=$2
insize=`stat -f %z $infile`

echo "Compressing $infile -> $outfile"

function progress {
  local outsize=`stat -f %z $outfile`
  local savings=`expr $insize - $outsize`
  local pct=`expr 100 \* $savings / $insize`

  echo "$insize -> $outsize ($pct%)"
}

if which -s pngcrush; then
  # pngcrush sometimes emits libpng warnings
  pngcrush -q -rem cHRM -rem gAMA -rem iCCP -rem sRGB -l9 -brute $infile $outfile 2>/dev/null
else
  # make sure $outfile exists
  cp $infile $outfile
fi

if which -s optipng; then
  optipng -q -o7 $outfile
fi

if which -s advpng; then
  advpng -q -z4 $outfile
fi

if which -s pngout; then
  pngout -q -s0 -y $outfile
fi

progress